1969 GMC C10 rear end suspension

[caribee]

The last owner of my 1969 GMC C10 truck 6 cylinder massacred the suspension by lowering it improperly. I have replaced the front coil springs and shocks to original on the front. On the rear end I added leaf springs over the axle and HD shocks. It now sits just like I want it and rides well. My question is whether I need to add one, two, or any at all rear track arm or rear traction bar set and if so, should they be trailing or go to the front?
What would be the proper way to install? I have seen the setup with one trailing arm attached to the differential on V-8 trucks, but my differential does not have the place to attach it. I am afraid of the rear axle shifting over time.

[bigdog55]

Gmc's generally don't come with trailering arms. leaf springs are stock. Chevy's normally come with trailering arms. That's one of the few differences between chevy and GMC.